Is it possible to get external memory for a Apple iPod Touch 8GB?

i am looking to get a ipod touch out of my christmas money i dont think 8GB is big enough for my needs so i am looking for external memory. i also need to know what model this is because i am also planing to get a case fo it. this is the link: http://www.argos.co.uk/static/Product/partNumber/9007815/Trail/searchtext%3EIPOD+TOUCH.htm#pdpAlternativeProducts i would like to thank in advance for all the help